today senator dianne feinstein takes on one of the most contentious gun ban issues. nancy cortes reports. >> reporter: this legislation is seen by many democrats as the first step in strengthening gun laws, but it's also the most controversial. it's called the assaults weapons ban of 2013 and it would reinstate the assault weapons ban that was allowed to lapse back in 2004. it would also restrict the number of bullets in high-capacity magazines. this is legislation that has been waiting in the wings for quite some time, but the lead sponsor, senator dianne feinstein of california is introducing it now in the wake of the sandy hook tragedy. most republicans and some democrats argue that an assault weapons ban is ineffective, that it doesn't do much to reduce gun violence, doesn't do much to deal with the real problem of mental illness and violates the second amendment. but the democrats by and large contend that studies show that the assault weapons ban did work when it was in place and that they plan to deal with things like mental illness and strengthening backgroun